1. Field of the Invention
The present invention relates to a sheet supplying apparatus used with a recording apparatus having a plurality of functions such as a copying function, a facsimile function, a printing function and the like, and a recording apparatus using such a sheet supplying apparatus.
2. Related Background Art
Normally, a recording apparatus includes an image reading portion, an image signal transmitting portion, and an image recording portion so that communication of image signals is effected, and a copying function is realized by driving the image reading portion and the image recording portion simultaneously. Further, in the image reading portion, there is provided a sheet supplying apparatus for separating plural originals one by one and supplying the separated original. Regardless of the communication function and the copying function, the original is supplied by using such a sheet supplying apparatus.
In FIG. 28 schematically showing the entire construction of a conventional recording apparatus, an original stacking plate 101 is constituted by an upper cover on which a plurality of originals S can be stacked. The recording apparatus comprises an image recording portion 102 for reading image information on the original S, a recording portion 103 comprised of a laser beam printer, an original convey portion 104, an image sensor 105 of close contact type for reading an image on the original, an original discharge tray 106, a laser scanner 107, an image forming portion 108, a photosensitive drum 109, a fixing portion 110, a cassette sheet supply portion 111, a recording sheet discharge tray 112, an upper original tray 113, a lower original tray 114, an operation portion 115, an auxiliary convey roller 116, a separation portion 117, a separation roller 118, and a reverse rotation roller 119.
First of all, an operator rests the originals S on the original stacking plate 101 with the imaged surfaces facing downside and then inserts the originals into the original convey portion constituted by the upper and lower original guides 113, 114. Then, the operator selects an operation mode by using selection keys on the operation portion 115. The operation mode may be a transmission mode, a copy mode, an image resolving power mode, a post-transmission stamp mode or the like.
When the original is sent or transmitted, after the original transmission mode is selected, the operator inputs the FAX telephone number of an receiver via the operation portion 115 and then depresses a start key on the operation portion. On the other hand, when the original is copied, the copy mode is selected, the operator inputs the copy number (number of parts) via the operation portion and then depresses the start key.
When the start key is depressed, the originals are sent to the separation portion 117 by the auxiliary roller 116. When the originals reach the separation portion 117, an lowermost original is separated from the other originals by the separation roller 118 (which tries to pull the lowermost sheet) and the reverse rotation roller 119 (which tries to return the laminated originals). The separated original is sent to the downstream original convey portion 104.
An image on the imaged surface (lower surface) of the original sent to the original convey portion is read by the image sensor 105 of close contact type. An analogue signal outputted from the image sensor 105 close contact type is subjected to image treatment such as shading correction, A/D conversion and the like. Thereafter, the signal is sent to a control portion (not shown) as image information. When the original is transmitted (facsimile transmission), the image information sent to the control portion is outputted to the circuit through a modem; whereas, when the original is copied, the image information sent to the control portion is outputted to the recording portion 103. After the image on the original is read, the original is discharged onto the original discharge tray. Accordingly, the originals are re-stacked with the imaged surface facing downside from the firstly supplied original to the lastly supplied original (so-called "face-down" and "page sequence").
When the original is copied, in the recording portion 103, scan light from the laser scanner 107 is illuminated on the photosensitive drum 109 of the image forming portion 108 in response to an image signal outputted from the control portion, thereby forming the image information on the photosensitive drum 109. Then, the image information is transferred onto a recording sheet P supplied from the cassette sheet supply portion 111 to the image forming portion 108. The recording sheet P to which the image information was transferred is sent to the fixing portion 110, where the image information is permanently fixed to the recording sheet. Thereafter, the recording sheet is discharged onto the recording sheet discharge tray. The recording sheets are stacked on the tray with the imaged surface facing upside from the first discharged sheet to the last discharged sheet (so-called "face-up" and "reverse page sequence"). In the case where the original is copied, when the recording sheets are stacked in a face-up fashion, since the imaged surface of the recording sheet can easily be ascertained, it is easy to check the image quality.
However, in the conventional technique as shown in FIG. 28, since the originals are read in page sequence and the recording sheets are stacked in the face-up fashion, there arises a problem that the recording sheets are stacked in the reverse page sequence. In order to stack the recording sheets in the same sequence as the original (page sequence), it is necessary to read the originals from the last page toward the first page and to stack the recorded recording sheet in the face-up fashion, or to read the original from the first page toward the last page and to stack the recorded recording sheets in the face-down fashion. However, in the former case, there arises a problem that, in the transmission (facsimile transmission), the information of the originals is sent from the last page. Further, in the latter case, there arises a problem that, in the copying operation, it is hard to check the image quality. To solve these problems, it is considered that the page sequence is reversed between the facsimile transmission and the copying operation, and the originals with page sequence or reverse page sequence are set in the sheet supplying apparatus. However, in this case, the handling of the originals becomes troublesome to frequently cause the mis-setting (upper/lower surface error), thus making the apparatus hard to use.
In consideration of the above circumstances, the inventors have proposed an improved sheet supplying apparatus capable of eliminating the drawbacks in the conventional technique shown in FIG. 28 (see Japanese Patent Publication No. 61-1335 (1986)). In this improved apparatus, two pair of combinations of sheet supply means and separation means are provided on two shafts, respectively so that sheets (originals) can be supplied from both an uppermost one and a lowermost one. Accordingly, if the improved sheet supplying apparatus is used with the recording apparatus shown in FIG. 28, it is not required that the page sequence is reversed or changed between the facsimile transmission and the copying operation, thereby making the recording apparatus easy to use.
However, in the above-mentioned improved apparatus, since there must be provided two pairs of combinations of the sheet supply means and the separation means having different coefficients of friction, the arrangement becomes complex and the number of parts is greatly increased, thereby making the sheet supplying apparatus very expensive, and, thus, the recording apparatus using such a sheet supplying apparatus is also expensive and complex.